Superfluidity breakdown of periodic matter waves in quasi one-dimensional annular traps via resonant scattering with moving defects

Abstract

We investigate, both analytically and numerically, the quasi-superfluidity properties of periodic Bose-Einstein condensates (BECs) in a quasi-one-dimensional (1D) ring with optical lattices (OL) of different kinds (linear and nonlinear) and with a moving defect of an infinite mass inside. To study the dynamics of the condensate we used a mean-field approximation describing the condensate by use of the Gross-Pitaevskii equation for the order parameter. We show that the resonant scattering of sound Bloch waves with the defect profoundly affect BEC superfluidity. In particular, a moving defect always leads to the breakdown of superfluidity independently of the value of its velocity. For weak periodic potentials the superfluidity breakdown may occur on a very long time scale (quasisuperfluidity) but the breakdown process can be accelerated by increasing the strength of the OL. Quite remarkably, we find that when the length of the ring is small enough to imply the discreteness of the reciprocal space, it becomes possible to avoid the resonant scattering and to restore quasi-superfluidity.

11 pages, 9 figures

References in corpus (6)

• Quantum-fluid dynamics of microcavity polaritons
• Superfluidity of Bose-Einstein Condensate in An Optical Lattice: Landau-Zener Tunneling and Dynamical Instability
• Decay of a superfluid currents in a moving system of strongly interacting bosons
• Resonant scattering of matter wave gap-solitons by optical lattice defects
• Acceleration and localization of matter in a ring trap
• Persistent current of atoms in a ring optical lattice

Cited by in corpus (2)

• Localized modes and dark solitons sustained by nonlinear defects
• Solutions of Nonlinear Polyharmonic Equation with Periodic Potential